The present invention relates to the decontamination arts. It finds particular application in connection with an automated system for leak testing, cleaning, sterilizing, and drying devices for medical, dental, mortuary, and pharmaceutical applications, and the like, and will be described with particular reference thereto. It should be appreciated, however, that the invention is also applicable to the decontamination of other devices in an automated processing system.
Medical devices, such as endoscopes, and other lumened instruments, are subjected to thorough cleaning and antimicrobial decontamination between each use. During medical procedures, the devices become coated with blood and other protein-rich body fluids. If the instruments are sterilized while they are coated with these materials, the high temperatures and/or chemicals used in the sterilization process tend to cause the materials to set as a hardened layer of biological residue that becomes difficult to remove. Not only do such residues present a barrier to sterilant penetration, but even when sterilized, they may later break down to form toxic substances which pose hazards to patients when the devices are reused.
Traditionally, such devices are often rinsed in a cleaning solution, such as an enzymatic cleaner, to remove the bulk of the blood and other body fluids from their surfaces. The rinsing process is generally carried out manually, by immersing the devices in a shallow tray of the cleaning solution. However, for devices such as endoscopes, the cleaning fluid may not penetrate the length of the internal lumen, leaving a portion of the endoscope to become coated with dried body fluids. Additionally, the biological materials and strong cleaners may pose hazards to personnel coming into contact with them.
High temperature sterilization processes, such as steam sterilization in an autoclave, are generally unsuited to the sterilization of endoscopes because of the delicate components and materials from which they are manufactured. The high temperature and pressure tend to curtail the useful life of endoscopes, rubber and plastic devices, lenses, and portions of devices made of polymeric materials and the like. High temperature sterilization alone does not clean. Any body fluids that are not removed prior to thermal sterilization are typically baked on to the instrumentation.
Instruments which cannot withstand the pressure or temperature of the oven autoclave are often microbially decontaminated with gas or vapor such as ethylene oxide gas or hydrogen peroxide vapor. Both require a separate cleaning operation. The ethylene oxide sterilization technique also has several drawbacks. First, the ethylene oxide sterilization cycle tends to be longer than the steam autoclave cycle. Second, some medical equipment can not be sterilized with ethylene oxide gas. Third, ethylene oxide is highly toxic and can present health risks to workers if not handled properly.
Biological materials remaining on the instruments after the cleaning process may pose hazards to personnel transferring the instruments to a sterilizer.
Liquid microbial decontamination systems are now utilized for equipment which could not withstand the high temperatures of steam sterilization. Peroxyacetic acid, or peracetic acid, is a useful sterilant and/or disinfectant for a variety of applications, including disinfection of waste and sterilization or disinfection of medical equipment, packaging containers, food processing equipment, and the like. It has a broad spectrum of activity against microorganisms, and is effective even at low temperatures. It poses few disposal problems because it decomposes to compounds which are readily degraded in sewage treatment plants.
In some situations, a technician mixes a disinfectant or sterilant composition with water and then manually immerses the items to be microbially decontaminated in the liquid composition. The high degree of manual labor introduces numerous uncontrolled and unreported variables into the process. There are quality assurance problems with technician errors in the mixing of sterilants, control of immersion times, rinsing of residue, exposure to the ambient atmosphere after the rinsing step, and the like. For sterilizing large instruments, however, a large receiving tray and a considerable quantity of decontaminant solution are used to accommodate and fully immerse the instruments. Manually filling the lumens of elongated instruments, such as endoscopes, was not always reliable.
Integrated decontamination systems, such as peracetic acid decontamination systems, have now been developed which provide a premeasured dose of a decontaminant in solution. Items to be sterilized are loaded into a receiving tray of a sterilization system and a cartridge of concentrated decontaminant inserted into a well. As water flows through the system, the decontaminant, which may be accompanied by surfactants and corrosion inhibitors, is diluted and carried to the receiving tray.
Spraying the exterior of the instruments, while flowing decontaminant solution through the lumens, would have advantages over full immersion of the devices in reducing the quantity of decontaminant solution used. However, because of the complex shape of endoscopes, the spray jets may not reach all of the surfaces of the device.
The present invention provides for a new and improved automated fluid delivery system for reprocessing endoscopes and the like which overcomes the above-referenced problems and others.
In accordance with one aspect of the present invention, a system for microbially decontaminating a device with at least one internal passage is provided. The system includes a chamber for receiving the device, a source of a microbial decontaminant solution, spray nozzles, disposed within the chamber, for spraying the decontaminant solution over an external surface of the device, and at least one connection port disposed within the chamber for supplying the decontaminant solution to the internal passage. A fluid distribution system fluidly connects the source of the decontaminant solution, the chamber, and the nozzles and connection port. The distribution system delivers the decontaminant solution to the nozzles and connection port and receives sprayed decontaminant solution from the chamber. A pump, fluidly connected with the fluid distribution system, pumps the decontaminant solution to the nozzles and connection port. A control system controls the delivery of the decontaminant solution to the nozzles and connection port.
In accordance with another aspect of the present invention, a method of cleaning and microbially decontaminating a device having at least one internal passage is provided. The method includes positioning the device within a chamber, spraying a washing solution over the device from nozzles within the chamber to remove soil from exterior surfaces of the device and delivering the washing solution to the internal passage of the device to remove soil from the internal passage of the device. The method further includes spraying a microbial decontaminant solution over the device from nozzles within the chamber to microbially decontaminate the exterior surfaces of the device and delivering the microbial decontaminant solution to the internal passage of the device to microbially decontaminate the internal passage of the device.
One advantage of the present invention is that an endoscope or other lumened device is cleaned and microbially decontaminated in a single automated process.
Another advantage of the present invention is that hazards posed to personnel by handling contaminated devices are minimized.
Another advantage of the present invention is that a decontaminant spray system ensures decontamination of all exterior surfaces of the device being decontaminated.
Another advantage of the present invention is that the device being decontaminated is supported in an optimum position for access by the sprayed decontaminant solution.
Still further advantages of the present invention will become apparent to those of ordinary skill in the art upon reading and understanding the following detailed description of the preferred embodiments.